Surface heating unit having selective concentric electric sheathed heating elements

ABSTRACT

A surface heating unit having circular electric sheathed heating elements. The electric heating elements selectively supporting round-bottom, Chinese wok-type cooking vessels as well as cnventional flat-bottom vessels on an electric range top or other such installation.

United States Patent [191 Behr et a1.

[ SURFACE HEATING UNIT HAVING SELECTIVE CONCENTRIC ELECTRIC SHEATHEDHEATING ELEMENTS [76] Inventors: Robert D. Behr; Seiko K. Behr, both of1 10 Queen St., Chestertown, Md. 21620 [22] Filed: Mar. 23, 1973 [21]Appl. No.: 344,273

[52] US. Cl 219/456, 219/433, 219/461 [51] Int. Cl. H05b 3/68 [58] Fieldof Search 219/433, 438, 444, 447, 219/455, 456, 461

[56] References Cited UNITED STATES PATENTS 919,843 4/1909 Fish 219/4332,250,357 7/1941 Challet 2l9/456 2,262,507 11/1941 Lightfoot.... 219/4562,263,350 l1/1941 Challct 219/456 2,270,293 l/l942 Grunder 219/456 [451July 30, 1974 2,272,658 2/1942 Challet 219/456 X 2,288,967 7/1942Challet 219/456 2,506,554 5/1950 Tuttle 219/455 X 2,515,579 7/1950 Allen219/456 X 2,725,455 11/1955 McOrlly 219/456 3,700,856 10/1972 Kullman219/456 X FOREIGN PATENTS OR APPLICATIONS 185,473 5/1956 Austria 219/455911,650 3/1946 France 219/455 Primary Examiner-Volodymyr Y. MayewskyAttorney, Agent, or Firm-J. B. Felshin; Marvin Feldman 5 7 ABSTRACTbottom vessels on an electric range to?) or other such installation.

16 Claims, 7 Drawing Figures 1 SURFACE HEATING UNIT HAVING SELECTIVECONCENTRIC ELECTRIC SHEATH-ED HEATING ELEMENTS This invention relates toa sheathed, rigid, electricheating element combination primarily of therange top variety.

The primary purpose of this invention is to render possible the use of acooking vessel of the type commonly known as Chinese wok on an electricstove or other such installation, while maintaining the same range topsurface area available to conventional flatbottom vessels.

The Chinese wok type vessel is a metallic cooking vessel, variable insize, with rounded bottom, so that it is in the shape of a hollowsphere, but never so much as a hemisphere, and the cooking is normallydone in the bottom 1 or 2 inches of this vessel. Heretofore, cooking insuch a vessel has been limited to gas flametype stoves because thetypical flat-surfaced heating element is not adapted to use with thewok-type vessel and the existing spring, resilient coil and other modelsare of too complicated construction, difficult to clean, or notvertically extendable enough to allow for the accommodation of so deepand curved a surface as that presented by the wok-type vessel in thenormal range top configuration.

It is hence an object of this invention to provide an electric,range-top heating element in which a roundbottom, wok-type vessel can beheated and cradled in upright position without rolling over.

Another object of this invention is to provide an electric, heatingelement of the character described, which will accommodate eitherconventional, flat-bottom vessels or round-bottom, wok-type vessels.

Still another object of this invention is to provide a strong anddurable, sheathed, electric heating element of the character described,which shall be relatively simple, inexpensive to manufacture, easy toclean and manipulate, and which shall yet be practical and efficient toa high degree in use.

Other objects of this invention will in part be obvious and in parthereinafter pointed out.

The invention accordingly consists in the features of construction,combination of coils, and arrangement of parts which will be exemplifiedin the construction hereinafter described, and of which the scope ofinvention will be indicated in the following claims.

FIG. 1 is a top plan view of the electric range-top, double, sheathed,heating element embodying the invention and composed of two separate andindependent, concentric, sheathed, heating coils;

FIG. 2 is a cross-sectional view taken on line 2--2 of FIG. 1;

FIG. 3 is a view similar to FIG. 2, but showing the interior heatingelement and its support removed to enable the outer heating element toheat and cradle the wok-type vessel.

FIG. 4 is a perspective view of a modified electric cooking stoveheating element which will accommodate either flat or curved bottomedcooking vessels;

.FIG. 5 is a cross-sectional view taken on line 5-5 of FIG. 4;

FIG. 6 is a perspective view of another modified form of the invention;and

FIG. 7 is a cross-sectional view taken in line 7-7 of FIG. 6.

2 Referring in detail to FIGS. 1, 2 and 3 of the drawings, numeral 10designates an electric cooking stove body, having a top wall 11, formedwith a round hole 12 tends radially inwardly, a flat annular horizontalwall or shoulder 16. Extending down from wall 16 is a rounded wall 17,having a central bottom hole 18 and receiving feet 41 of tripod support40. Said cup 13 has an opening 19 at one side for the purposehereinafter appearmg.

Fixed to the stove body 10 in any suitable manner (not shown) is a box20, open at its'inner side and located opposite opening 19 in the cup13.

Extending into box 20 are a pair of electric conductors 22, formed withresilient snap terminal prongs 23, and another such pair of conductors24, provided with similar resilient snap terminal prongs 25. Conductors22 and 24 connect to sources of electric energy. Such terminalconductors are known for electric ranges. On shoulder 16 are three,equiangularly-spaced, radial, vertical ribs 16a, fixed thereto in anysuitable manner. The function of these ribs is the support of theexterior heating element 30.

Element 30, resting on said ribs 16a, has an annular split portion 30a,from the ends of which end portions 31 and 32 extend downwardly. Fromportions 31 and 32 horizontal end portions 31a and 32a extend radiallyoutwardly and pass out of the cup 13 through opening 19 and into the box20 through the open end thereof. Said split annular or circular portion30a has a larger, flat, horizontal surface 30b and a broad, inner,slightly curved surface 30c to conform to the surface of a woktype,cooking vessel W. This surface form is distinct from that of ordinaryrange-top, heating elements in that it presents a broad heating surfacelaterally on the inside as well as at the upper surface, so that whenthe inner element is removed the wok-type vessel may be heatedlaterally, or when it is in place, an ordinary, flatbottom vessel may beheated on its upper surface.

End portions 31a and 32a terminate in terminal knobs rotatably receivedin the snap prongs 25. The heating element 30 is thus energized throughthe conductors 24. Proper switch means to turn the element on and off isprovided in the well known manner. Element 30 is removable, but forcleaning pruposes only.

Disposed in the cup and resting on the bottom curved portion 17 of saidcup is the tripod support 40 having three legs 41, fitting in cup 13,and radiating portions 42 and a top cap 43. The radiating portions ofthe support 40 are in a plane just below the plane of the underside ofsheathed element 30. Either fixed to or resting on said radiatingportions 42 of the support 40 is the inner, sheathed, heating element45, which has a portion 45a, spiral in shape, as shown in FIG. 1, lyingin the plane of element 30. Said spiral portion 45a has only a flatupper surface 45b in the plane of flat surface 30b of split annularportion 30a for the heating of flatbottom vessels.

At the inner end of element 45 is a downwardly extending portion 46 fromwhich a horizontal portion 47 extends radially outwardly, passingthrough opening 19 in cup 13 and into box 20 and terminating in a knobminals 23.

Extending from the outer end of the spiral portion of element 45 is adownwardly extending portion 48 from which a horizontal portion 49extends outwardly in parallel relation to portion 47, passing outthrough opening 19 in cup 13 and into box and terminating in a knobterminal 47a, swivelly snap-fitted into the other snap terminal 23, inthe well-known manner.

It will now be seen that when both elements 30 and 45 are used,flat-bottom cooking vessles can be placed on the said elements. Suchvessels rest on surfaces 30b and 45b. If it is desired to cook with around-bottom, Chinese wok-type cooking vessel, the inner element 45 maybe swung up to the dot-dash position of FIG. 2 and then pulled out andremoved along with its tripod support 40.

Then a Chinese wok-type cooking vessel W can be placed on the stove andit will contact, cradle and center on, and'be heated by the broad innersurface 30c of the round or circular portion 30a of the larger electricelement 30, to permit cooking and to prevent the rounded vessel fromrolling over.

Referring now to FIGS. 4 and 5, there is shown a heating element 60illustrating a modified form of the invention. In this modification, thesingle heating element 60 has means for supporting both a flat bottomwalled cooking vessel as well as a Chinese type wok cooking vessel witha rounded bottom. Element 60 has a top circular portion 61 which is in ahorizontal plane but somewhat less than 360 in angular extent. At oneend of said circular portion 60 is an outwardly extending portion 61afrom which there extends downwardly a portion 62 from which a horizontalportion 63 extends radially outwardly. Extending from the other end ofcircular portion 61 is a spiral portion 65 formed in a part sphericalsurface and decreasing in radius downwardly to a point 66 from which aradial portion 67 extends outwardly. Extending downwardly from portion67 is a portion 68 parallel to portion 62 (but shorter than said portion62). Extending outwardly from portion 68 is a portion 69 parallel to andat same horizontal level as portion 63. Said portions 63, 69 terminatein knobs 70 (like knobs 47a, of FIG. 2) to be received in snap terminals(like terminals 23 of FIG. 2).

Annular portion 61 has a top flat horizontal surface 610 and an innercurved surface 61b conforming to the outer surface of a wok type cookingvessel. Spiral element 65 has a top flat horizontal surface 65a and aninner curved surface 65b conforming to the contacting surface of a woktype cooking vessel W mounted on or contacting surface 61b.

A Chinese wok type cooking vessel will cradle and be supported inupright position in portion 65 of the element 60.

Thus element 60 will support flat bottomed as well as round bottomcooking vessels.

In FIGS. 6 and 7 there is shown elements 80 and 81 which are coaxial.Element 80 is at a higher level than element 81 and has a somewhat lessthan circular horizontal portion 82 from the ends of which portion 83extend downward. Extending from portion 83 are parallel horizontalportions 84 terminating in knobs 85.

Element portion 82 has a top flat horizontal surface 81a and an innercurved surface 82b.

The lower element 81 has a somewhat less than circular portion 86 in ahorizontal plane and of a diameter less than thediameter of circularportion 82 of element 80. Extending down from the ends of portion 86 arevertical parallel portions 87 from which parallel horizontal portions 88project outwardly and terminate in knobs 89.

Portion 86 of element 81 has a top fiat horizontal surface 860 and aninner curved surface 861) which matches curved surface 821) so that awok type cooking vessel W will cradle in and contact surfaces 82b, 86b.

The knobs 85 and 89 are received in snap terminals (not shown but liketerminals 23 of conductors receiving electric energy).

A cooking vessel with a flat bottom can rest on top surface 81a ofelement 80. A Chinese type wok or any cooking vessel with a roundedbottom can be placed on both elements 80, 81 as illustrated in FIG. 7.The upper element is like element 30 of FIGS. 1 and 2 and may besupported in a reflecting cup 13 as shown in FIG. 2. The lower element81 may be supported in a reflecting cup 13 in any suitable manner. Itmay rest on the inside of the cup 13 or on a support placed in the cup.

.The heating element 81 may be removed if desired to cook with heatingelement 80 alone. The heating element 80 may be removed to cook withelement 81 alone.

It will thus be seen that there is provided an article in which theseveral objects of this invention are achieved, and which is welladapted to meet the conditions of practical use.

I As possible embodiments might be made of the above invention, and asvarious changes might be made in the embodiments above set forth, it isto be understood that all matter herein set forth or shown in theaccompanying drawings, is to be interpreted as illustrative only.

We claim:

1. A combination comprising a top wall having a hole, a reflecting cupmounted on said wall and projecting down into said hole and having arounded wall, electric heating element means provided with end electricterminals and comprising means to selectively support and heat either aflat bottomed cooking vessel or a round bottomed cooking vessel, saidmeans comprising a pair of sheathed, tubular electrical coaxial innerand outer heating element portions, and means on said cup to supportsaid element portions, said element portions being so arranged as toselectively support either a flat bottomed or a round bottomed pot.

2. The combination of claim 1, said portions comprising parts of asingle heating element.

3. The combination of claim 2, one of said portions having a top, flat,horizontal surface and an inner curved surface, and said other portionshaving an inner curved surface.

4. The combination of claim 1, said portions comprising a pair ofseparate and separable heating elements, said heating elements eachhaving ends and electric terminals at said ends thereof.

5. The combination of claim 4, one heating element having a top, flat,horizontal surface and an inner curved surface and said other heatingelement having an inner curved surface.

6. The combination of claim 1, said heating element means having a topflat horizontal surface and an inner curved surface.

7. The combination of claim 1, a reflecting cup adapted to be fittedinto a hole in the top wall of a stove body, said reflecting cup havingmeans to engage the stove body to support said cup on said body, meanson said cup to support the outer electric heating element portion, andmeans removably mounted in the cup to support said inner electricheating element.

8. A combination comprising a first outer electric sheathed, tubularheating element and a second inner separate electric sheathed, tubularheating element coaxial with and separable from said first heatingelement and of less diameter than said first heating element saidheating elements each having ends and terminals at said ends, a top wallhaving a hole, a reflecting cup in said hole and supports in said cupfor said heating elements.

9. The combination of claim 8, said heating elements being located inthe same plane to support a flat bottomed cooking vessel placed on bothsaid elements, said inner element being removable to allow a roundbottomed cooking vessel to be supported on said outer element.

10. The combination of claim 9, said first heating element beingcircular, said second heating element being spiral in shape.

11. The combination of claim 8, said heating elements being located indifferent horizontal planes.

12. The combination of claim 8, said first heating element being at ahigher level than said second heating element 13. The combination ofclaim 12, said first and second heating elements being circular.

14. The combination of claim 12, said first heating element being of alarger diameter than said second heating element.

15. The combination of claim 8, said first heating element having a top,flat, horizontal surface and an inner curved surface, said secondheating element having a fiat, top, horizontal surface.

16. A combination comprising, an electric sheathed tubular heatingelement including a split circular element portion, terminals at theends of said element, whereby a flat bottomed cooking vessel can beplaced on top of said split circular portion and a curved bottom cookingvessel can be cradled in said split circular element portion to projecttherebelow, a top wall having a hole, a reflecting cup on said wall andin said hole and means on said cup to support said heating element, saidheating element having a flat top surface and an inner curved surface.

1. A combination comprising a top wall having a hole, a reflecting cupmounted on said wall and projecting down into said hole and having arounded wall, electric heating element means provided with end electricterminals and comprising means to selectively support and heat either aflat bottomed cooking vessel or a round bottomed cooking vessel, saidmeans comprising a pair of sheathed, tubular electrical coaxial innerand outer heating element portions, and means on said cup to supportsaid element portions, said element portions being so arranged as toselectively support either a flat bottomed or a round bottomed pot. 2.The combination of claim 1, said portions comprising parts of a singleheating element.
 3. The combination of claim 2, one of said portionshaving a top, flat, horizontal surface and an inner curved surface, andsaid other portions having an inner curved surface.
 4. The combinationof claim 1, said portions comprising a pair of separate and separableheating elements, said heating elements each having ends and electricterminals at said ends thereof.
 5. The combination of claim 4, oneheating element having a top, flat, horizontal surface and an innercurved surface and said other heating element having an inner curvedsurface.
 6. The combination of claim 1, said heating element meanshaving a top flat horizontal surface and an inner curved surface.
 7. Thecombination of claim 1, a reflecting cup adapted to be fitted into ahole in the top wall of a stove body, said reflecting cup having meansto engage the stove body to support said cup on said body, means on saidcup to support the outer electric heating element portion, and meansremovably mounted in the cup to support said inner electric heatingelement.
 8. A combination comprising a first outer electric sheathed,tubular heating element and a second inner separate electric sheathed,tubular heating element coaxial with and separable from said firstheating element and of less diameter than said first heating elementsaid heating elements each having ends and terminals at said ends, a topwall having a hole, a reflecting cup in said hole and supports in saidcup for said heating elements.
 9. The combination of claim 8, saidheating elements being located in the same plane to support a flatbottomed cooking vessel placed on both said elements, said inner elementbeing removable to allow a round bottomed cooking vessel to be supportedon said outer element.
 10. The combination of claim 9, said firstheating element being circular, said second heating element being spiralin shape.
 11. The combination of claim 8, said heating elements beinglocated in different horizontal planes.
 12. The combination of claim 8,said first heating element being at a higher level than said secondheating element.
 13. The combination of claim 12, said first and secondheating elements being circular.
 14. The combination of claim 12, saidfirst heating element being of a larger diameter than said secondheating element.
 15. The combination of claim 8, said first heatingelement having a top, flat, horizontal surface and an inner curvedsurface, said second heating element having a flat, top, horizontalsurface.
 16. A combination comprising, an electric sheathed tubularheating element including a split circular element portion, terminals atthe ends of said element, whereby a flat bottomed cooking vessel can beplaced on top of said split circular portion and a curved bottom cookingvessel can be cradled in said split circular element portion to projecttherebelow, a top wall having a hole, a reflecting cup on said wall andin said hole and means on said cup to support said heating element, saidheating element having a flat top surface and an inner curved surface.